Farcaster
Open Frames isn't officially supported by Farcaster, but most of the Open Frames properties are directly compatible with Farcaster Frames, and libraries for building Frames make it easy to support both conventions.
Frames Servers that wish to handle both Farcaster and Open Frames interactions are recommended to include a complete set of both
of:andfc:framemeta tags. If a complete set of Open Frames tags are not present in the page, Client Applications may choose to fall back to equivalentfc:frametags if theof:accepts:$protocol_identifiertag is present.
Learn more about Farcaster compatibility in the Open Frames spec.